1. Field of the Invention
The present invention relates to an imaging device, a colorimetry device, and an image forming apparatus.
2. Description of the Related Art
Conventionally, an imaging device has been known that images a patch recorded on a recording medium by an image forming apparatus using a coloring material such as ink, and that calculates a colorimetry value of the patch by converting an RGB value of the patch obtained by imaging into a color specification value in a standard color space (for example, Japanese Laid-open Patent Publication No. 2013-224924). The colorimetry value of the patch calculated by the imaging device is used for color adjustment in the image forming apparatus. Moreover, color adjustment in the image forming apparatus can be performed by using the RGB value obtained by imaging.
In this type of imaging device, an illumination light source such as a light emitting diode (LED) to illuminate an imaging range of a sensor unit that images an image is provided. Because the illumination light source has a directivity, when intense light of the illumination light source reflected by specular-reflection within the imaging range of the sensor unit enters the sensor unit, a proper RGB value cannot be obtained, and there is apprehension that it causes a problem in colorimetry of the patch, color adjustment of the image forming apparatus, and the like. Therefore, the imaging device described in Japanese Laid-open Patent Publication No. 2013-224924 has a configuration that a light diffuser is arranged in an optical path of light of direction reflection, and light from a light source is diffused by this light diffuser to a different direction from a sensor unit.
However, with the configuration described in Japanese Laid-open Patent Publication No. 2013-224924, it is difficult to avoid entrance of entire reflected light that is reflected on the light diffuser into the sensor unit, and there is a case in which a signal in a region in which the reflected light from the light diffuser forms an image can approach the saturation level. There is a problem that if the signal of the region of the light diffuser approaches the saturation level, it becomes difficult to acquire an RGB value that is used for colorimetry of a patch or color adjustment of an image forming apparatus properly from an image due to influence of flare, smear, blooming, and the like.